Device and process for measuring and analysing spectral radiation, in particular for measuring and analysing color characteristics

Apparatus for measuring and analysing spectral radiation within a predetermined wavelength range and particularly for detecting the characteristics of colors, comprising:

• a number of N1 radiant sources which emit radiation which is distributed spectrally over a wavelength range which lies, at least partially, within said predetermined wavelength range, where the spectral characteristics of said individual radiant sources differ from one another and N1 is greater than or equal to 1,
• sensor apparatus which detects radiation within said predetermined wavelength range and generates an electrical signal which is representative of the intensity of the detected radiation,
• a control unit which controls the radiation of said apparatus and which causes the radiant sources to be actuated in predetermined combinations at successive intervals of time,
• a storage device, in which the values detected by means of the sensor apparatus for the respective combinations of radiant sources are recorded and stored,
• the control unit calculates values from said stored values for identifying the spectral characteristics of the radiant sources,
• characterized in that
• the radiant sources are selected in such a way that their spectral characteristics overlap with said predetermined wavelength range,
• that the spectral characteristics of the light sources furthermore are such that the characteristics of at least N2 of said light sources are linearly independent of one another,
• that said sensor apparatus comprises a number of M1 sensors whose spectral characteristics in the predetermined wavelength range overlap in such a way that the entire predetermined wavelength range is covered, where M1 is greater than or equal to 1;
• that the spectral characteristics of the sensors are furthermore such that the characteristics of at least M2 of said radiant sources are linearly independent of one another,
• that the product P=N2*M2 derived from the multiplication of the values for N2 and M2 is greater than 1;
• that in said storage device a number of P calibration functions are stored which span the predetermined wavelength range at least in part, and which define the relationship between the spectral intensity distribution of P standard samples, which is measured by means of the individual device, and their known reflectance spectra, the spectral characteristics of the reflectance spectra being linearly independent of one another and overlapping, at least partially, in such a way that the entire wavelength range is recorded and that by combining said calibration functions with the measured values for the radiation to be measured and which are obtained by means of the sensor apparatus, the spectral course of the radiation to be measured can be determined.